BCA 1 against Brown rot
- To characterize both biological control agents, Penicillium frequentas and Bacillus subtillis, in order to meet Directive 2001/36 EEC requirements and to develop products suitable to be registered and commercialized
- To optimize the production processes of biological control agents to obtain commercially feasible scaling-up and downstream processing protocols
- To develop formulation strategies for each biological control agent to prolong shelf life and improve efficacy against brown rot in stone fruit under practical conditions
- To develop and validate control strategies based on the biological control agents, to determine doses, cost-effectiveness and application times adapted to different European stone fruit producing regions.
Penicillium frequentans 909
Penicillium frequentans is a common colonizer of peach twigs and flowers. Isolate 909, isolated by the INIA research group, reduced twig blight caused by M. laxa in experimental stone fruit orchards and pre- and postharvest brown rot caused by M. laxa and M. fructigena. Competition and antibiosis are the mode of action of this fungal antagonist, although antibiotics were only detected in potato dextrose broth.
Research group INIA has also developed a mass production method of P. frequentans conidia by solid fermentation at laboratory scale. P. frequentans produced 108 to 109 conidia g−1 dry weight substrate with viability higher than 80%, but the viability of these fresh conidia declined 30 days after storage at room temperature.
Formulation studies have been conducted at laboratory scale. Fluidized bed drying gave best results in combination with adjuvants such as stabilizers and adherents to improve stability and effectiveness. P. frequentans conidia can be dried by fluid bed-drying maintaining 100% viability after the drying processes, and 28% after 180 days storage at room temperature. Dried conidia maintained efficacy against brown rot.
Both biocontrol agents, Penicillium frequentans 909 and Bacillus subtilis CPA-8, have shown good potential for development as commercial products against the brown rot of stone fruit.